Magnetron amplifiers



Feb. 7, 1961 E. c. DENCH MAGNETRON AMPLIFIERS Original Filed Nov. 8, 1951 //v l ENTOR EDWARD C. DENCH' A T7'ORNEV 2,971,121 Patented Feb. 7, 1961 r as atcnt anode members 12 and the spaces defined therebetween constitute a signal Wave transmission network having a 2,971,121 high-frequency pass filter characteristic. At one point in the anode structure, the members 12 and the conduc- .MAGNETRN AMPLIFIERS tive strapping 13 have been eliminated such that the Edward C. Dench, Needham, Mass., assign'or to Raytheon transmission network is of a non-reentrant type. A Company, a corporation of Delaware signal input coupling structure 14 is connected to one end of the signal wave transmission network by connectgg i ggf g gg gg i 1 gbgg? ?$5 ing one of the conductive straps 13 to the inner conductor and this applicafian A 1957, i 658,913 15 of a coaxial line having an outer conductor 16. The 1 coaxial line comprising conductors 15 and 16 extends '11 Claims. (Cl. 31"539.3) outwardly through an aperture in anode cylinder 11 with outer conductor 16 being sealed to said aperture. Outer conductor 16 is sealed to innerconductor 15 through a This is a division of my application, Serial No. 255,499, 15 ceramic seal 17 which insulatedly supports inner confiled November 8, 1951, now Patent No. 2,809,328. ductor 15 with respect to outer conductor 16. The other This invention relates to electron discharge devices and end of the transmission line is connected to an output more particularly to discharge devices or the magnetron coupling device comprising an inner conductor amplifier type. outer conductor 20 and a ceramic seal 21 similar, respec- In copending application, Serial No. 81,804, filed 20 y, 0 members and 17 of input coupling March 16, 1949, by William C. Brown, now Patent No. device 14. 2,673,306, dated March 23, 1954, there is disclosed a Extending inwardly from anode cylinder 11, in the magnetron amplifier wherein th od f a cavity type space between the ends of the signal wave transmission of magnetron struoture is constructed as a non-reentrant network, iS a C ndu m m r 22- Mcm l 22 extends signal Wave transmission network having input and output inwardly from anode cylinder 11 for fillbsmntially the means connected, respectively, to the ends thereof. It Same dis-fiance s anode members and is PP P Y has been found that the operation of devices of this type dimensioned to Serve as a radio frequency Choke, thereby is quite critical since, if the gain is too high for a given Mel/6min" Coupling 0f Signal Waves appearing the set of impedance-matching conditions at the input and output device directly across to the input device. output of the device, oscillations may occur. Positioned in the space defined by the inner ends of This invention di lo e mean whereby th gain a d the anode members 12 is a cathode structure 23 comprisother operating conditions of the device may be adjusted. i g a Cathode Cylinder 24 'WhOSB Outer Surface is covered Briefly, this is accomplished by placing auxiliary elecwith electron-emissive material. The upper and lower trodes outside the paths of electrons which pass adjacent nds of cathode cylinder 24 are covered by upper and the signal wave transmission network, portions of said lower end plates 25 and 26, respectively. Rigidly atelectrodes being positioned adjacent the cathode of the tach d to lower end plate 26 is a cathode support cylinder device, and portions of the electrodes extending toward 27 which extends downwardly through an aperture in a the anode structure of the device. By insulating these lower end cover 28 which is hermetically sealed to the electrodes with respect to the anode and the cathode, a lower end of anode cylinder 11. Support cylinder 27 is biasing potential may be applied thereto, and the gain, rigidly attached to a cup member 29, which, in turn, is as well as other operating conditions of the device, may sealed to a ceramic seal 30 surrounding anode support be adjusted by adjusting said biasing potential. cylinder 27. Seal so is, in turn, attached to a cylindrical There is disclosed herein a first embodiment of this conductive member 3-1 surrounding support member 27 invention, wherein the anode structure surrounds a cylinsp thfireffo'm, and Sealed into a r s SHITOllIlding drical cathode structure spaced therefrom such that the the aperture in cover plate 28 through which support cathode structure emits electrons along substantially the member 27 passes. Positioned inside support member entire length of the anode structure from the input to 27, which is hollow, is a conductive rod 32 which is the output thereof. The auxiliary electrodes are in the spaced from support member 27, one end of which exform of discs positioned at the ends of the cathode structends into cathode cylinder 24 where it is connected to ture, insulated therefrom and extending radially out toone end of a heater coil 33, the other end of heater coil ward the anode structure. These auxiliary electrode discs 33 being connected to the cathode cylinder 24. Contake the place of the conventional end shields commonly ductor 32 extends outwardly through the lower end of used in magnetron structures to prevent movement of support member 27 and is insulatedly sealed thereto by the electrons in a direction axial to the cylindrical cathode. means of a ceramic seal 34 in a well-known manner. By

Other and further objects and advantages of this invenapplication of a potential between a connector 35 attion will be apparent as the description thereof progresses, tached to conductor 32 after it passes seal 34 and support reference being had to the accompanying drawings wherecylinder 27 which is connected through lower'end plate in: 26 to the cathode cylinder 24, a current may be caused Fig. 1 illustrates a longitudinal cross-sectional view of to flow through the heater coil 33, thereby heating the a first embodiment of this invention taken along line cathode cylinder 24 to electron-emitting temperature. 1 1 of 'Fig. 2; and Positioned above and below the cathode structure 23 Fig. 2 illustrates a partially broken away transverse are conductive discs 36 and 37, respectively, said discs cross-sectional view of the device shown in Fig. 1. extending outwardly to a point near the inner ends of Referring now to Figs. 1 and 2, there is shown an anode anode members 12. Discs 36 and 37 are spaced from structure 10 comprising an anode cylinder 11. Extending the cathode 23 and are rigidly attached together through radially inwardly from the inner surface of anode cylinconductive rods 38, which extends through apertures in der 11 is a plurality of anode members 12 comprising end plates 25 and 26, respectively, spaced therefrom. substantially rectangular planar members which lie par- Lower disc 37 has an aperture therein to allow the pasallel to the axis of cylinder '11. Members 12 are altersage of support cylinder 27 therethrough without connately connected at points near their inner ends on the tact therewith. The auxiliary electrode structure comupper and lower edges thereof by conductive straps 13, in a well-known manner, such that the straps 13, the

prising discs 36 and 37 is rigidly supported with respect to the anode structure 10 and the cathode structure 23 by means of rods 39 rigidly attached to lower disc 37 and passing through apertures in lower cover plate 28, rigidly sealed thereto by means to ceramic buttons 40 positioned in the apertures in cover plate 28, surrounding and sealed to rods 39. By application of a suitable potential to the lead-in support rods 39, the auxiliary electrode comprising discs 36 and 37 may be maintained at any desired potential with respect to the cathode structure 23 or the anode structure 10.

While is is preferable that the auxiliary electrode structure be biased somewhat negative with respect to the cathode structure 23, it is to be clearly understood that this invention is not limited thereto since, if a certain amount of electron collection by the auxiliary electrode structure may be tolerated, an improvement in gain may be possible by biasing the auxiliary electrode structure positive with respect to the cathode structure 23.

The upper end of the anode cylinder 11 is closed by an upper cover plate 41, and a magnetic field is produced in the space between the inner ends of the anode members 12 and the cathode cylinder 24 by any desired means, such as a permanent magnet 41a or an electromagnet.

This completes the description of the embodiment of the invention described herein. However, many modifications thereof will be apparent to persons skilled in the art. For example, the device shown in Figs. 1 and 2 may be a linear device instead of a circular one. Furthermore, if desired, a blocking member could be attached to the cathode structure in the device of Figs. 1 and 2 at a point adjacent the radio-frequency choke member 22 to prevent electrons from continuing around the cathode from the output of the device to the input. Accordingly, it is desired that this invention be not limited to the particular details of the embodiments illustrated herein, except as defined by the appended claims.

What is claimed is:

1. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along the region between said structure and said source at a velocity substantially equal to the velocity of propagation of said wave energy, and an output amplitude control electrode structure insulated from said energy propagating structure and said source and including an electrically-conductive member positioned adjacent and outside said region and outside said structure.

2. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along the region between said structure and said source at a velocity substantially equal to the velocity of propagation of said wave energy, and an amplitude control electrode structure insulated from said energy propagating structure and said source and including an electrically-conductive member positioned adjacent and outside said region, and means for supplying an electrical potential to said control electrode for controlling the amplitude of said wave energy to said output.

3. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along the region between said structure and said source at a velocity substantially equal to the velocity of propagation of said wave energy, and an amplitude control electrode assembly insulated from said energy propagating structure and said source and including two spaced electrically-conductive electrodes positioned adjacent and outside said region and disposed on opposite sides of said region, and means for supplying an electrical potential to said control electrode assembly for controlling the amplitude of said wave energy to said output.

4. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along the region between said structure and said source at a velocity substantially equal to the velocity of propaagtion of said wave energy, said electrons making more than one traversal past a given point along said structure, and an amplitude control electrode structure insulated from said energy propagating structure and said source and including two spaced electrically-conductive members positioned adjacent and outside said region and disposed on opposite sides of said region and facing said region and means for supplying an electrical potential to said control electrode structure for controlling the amplitude of said wave energy to said output. I

5. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along an interaction space between said source and said structure at a velocity substantially equal to the velocity of propagation of said wave energy, and an output amplitude control electrode structure insulated from said energy propagating structure and said source and including an electricallyconductive ring positioned adjacent and outside said interaction space, the material of said ring being juxtaposed with said s ace.

6. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy, to an output, a source of electrons spaced from said structure, means for directing electrons from said source along said structure at a velocity substantially equal to the velocity of propagation of said wave energy, and an amplitude control electrode including at least one electrically-conductive member positioned adjacent and outside said structure insulated from said energy propagating structure and said source and facing said structure and insulated therefrom, and means for supplying an electrical potential to said control electrode structure for controlling the amplitude of said wave energy to said output.

7. An electron discharge device comprising a slow wave energy propagating structure having first and second ends for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along the region between said structure and said source at a velocity substantially equal to the velocity of propagation of said wave energy, said means for directing including means for producing a magnetic field transverse to said region, and an output amplitude control electrode structure supported electrically insulated from the remainder of the device and including an electrically-conductive member positioned adjacent and outside said region and facing said region.

8. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along said structure at a velocity substantially equal to the velocity of propagation of said wave energy, and an output amplitude control electrode assembly supported electrically insulated from the remainder of the device and including two spaced electrically-conductive members positioned adjacent and outside said structure, said members being disposed on opposite sides of said structure.

9. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic Wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along said structure at a velocity substantially equal to the velocity of propagation of said wave energy, and an amplitude control electrode assembly supported electrically insulated from the remainder of the device and including two electrically-conductive members positioned adjacent and outside said structure and disposed on opposite sides of said structure, said members being electrically at the same potential, means for supplying an electrical potential to said members for controlling the amplitude of said wave energy to said output.

10.An electron discharge device comprising a slow wave energy propagating structure having first and second ends for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure and constructed to emit electrons at several positions over a major portion of the region between said structure and said source at a velocity substantially equal to the velocity of propagation of said wave energy, means for directing electrons from said source along said region, and an amplitude control electrode assembly supported electrically insulated from the remainder of the device and including two spaced electrically-conductive members positioned adjacent and outside said region and disposed on opposite sides of said region and facing said region, and means for supplying an electrical potential to control members for controlling the amplitude of said wave energy to said output.

11. An electron discharge device comprising a slow wave energy propagating structure for transmitting electromagnetic wave energy to an output, a source of electrons spaced from said structure, means for directing electrons from said source along a region between said source and said structure at a velocity substantially equal to the velocity of propagation of said wave energy, an amplitude control electrode structure supoprted electrically insulated from the remainder of the device and positioned adjacent and outside said region, said members being arranged coextensive with and facing said region, and means for supplying an electrical potential to said control electrode structure for controlling the amplitude of said wave energy to said output.

References Cited in the file of this: patent UNITED STATES PATENTS 2,412,372 Usselman Dec. 10, 1946 2,416,298 Fisk Feb. 25, 1947 2,462,137 Smith Feb. 22, 1949 2,501,152 Becker Mar. 21, 1950 2,566,479 Becker Sept. 4, 1951 2,620,458 Spencer Dec. 2, 1952 2,730,648 Lerbs Jan. 10, 1956 2,768,328 Pierce Oct. 23, 1956 2,784,345 Spencer Mar. 5, 1957 2,802,141 Brown et al. Aug. 6, 1957 OTHER REFERENCES Article by J. Groszkowski et al., pages 771 to 777, Free. of I.R.E. for May 1936, vol. 24, No. 5. 

